Acid Protease Production from Neosartorya fischeri

A three-factor, five-level central composite design was used to optimize acid protease production from wheat bran by Neosartorya fischeri var. spinosa IBT 4872. Initial water content, incubation temperature and phosphate concentration significantly affected acid protease production. Initial water content showed the strongest effect on the enzyme production. No interaction was observed among the variables. The validity of the model was confirmed by verification tests. Optimal conditions for acid protease production were: initial substrate water content, 53 mL H2O/100 g; phosphate concentration, 0.86 mol/L; and temperature, 30 °C. The enzyme yield was 1.59 units/mL (8.83 units/g wheat bran). Acid proteases are widely used in cheese-making, baking and meat tenderization.